A new study has revealed chronic marijuana use by teenagers is not linked to the later development of physical or mental issues.

There was no link between adolescent marijuana use and the development of health problems later.

The drug, also known as cannabis, remains a heated topic of debate around the country. Last month, Oregon became the fourth state to legalize the use of recreational marijuana, following Alaska, Colorado and Washington.

The public perception of the drug is shifting, and it is likely a host of other US states will follow suit and consider legalizing the herbal drug.

Marijuana remains the most widely used illicit drug in the US, and many studies have already investigated its effects. Previously, long-term chronic use of the drug was linked to a host of unwanted side effects.

According to the National Institutes of Health (NIH), chronic use of the drug can lead to impairment of the brains’ cognitive functions and increase the risk of developing mental health problems, such as depression.

In addition, physical effects from long-term use can include breathing problems, a faster heart rate and problems with child development during and after pregnancy.

However, new studies have investigated the increasingly complex effects of the drug and its potential medicinal properties. Last month, Medical News Today reported on how the drug helps bones to heal.

Lead researcher Jordon Bechtold, PhD, from the University of Pittsburgh Medical Center, PA, and his team set out to review the full effect of the drug over an extended period of time by tracking participants for more than 2 decades.

Published in the journal Psychology of Addictive Behaviors, the study analyzed more than 400 participants from the late 1980s.

The research was a result of other work, the Pittsburgh Youth Study, which began as a means to analyze the development of social and health problems among young men by following 14-year-old male Pittsburgh public school students.

More than 400 participants were analyzed, which was made up of 54% black, 42% white and 4% of other race and ethnicities.

At first, the boys were interviewed every 6 months. After 18 months, the interviews were conducted annually until they were 26. Between 2009-2010, participants were once again interviewed when they reached 36 years old.

Participants were divided into four groups depending on their marijuana use. They were:

Low or none users (46%)

Early chronic users (22%)

Participants who only smoked marijuana during adolescence (11%)

Participants who only smoked marijuana during adolescence and continue to do so (21%).

Marijuana not a significant factor

It was found early chronic users reported a much higher use of marijuana. This rapidly increased during their teens and peaked at the age of 22, when the drug was used for more than 200 days per year on average.

Fast facts about marijuana

Marijuana is the most widely used illicit drug in the US

More than half of new illicit drug users begin with marijuana

Every day, 3,287 teenagers in the US use marijuana for the first time.

The study found the four groups were not significantly different when assessing physical and mental health issues. Researchers also concluded there was no difference in the findings based on race or ethnicity.

Dr. Bechtold describes the result as “a little surprising” in relation to previous studies and the traditional warnings about the chronic use of the drug.

However, the study does acknowledge its limitations. The first being the sample group was only limited to males. This is particularly important, as females may be at more risk of substance abuse, according to a 2014 study.

In addition, the assessment of the patients only took place in their mid-30s, which may be too early for the full effects of past marijuana use to emerge.

Also, the interviews employed in the study relied on participants to accurately self-report any health problems. It is possible for patients to be either unaware of their own health problems or dishonest about their state of health.

Last month, MNT reported on how scientists were able to isolate the unwanted side effects of marijuana, but arguments continue to rage from both sides regarding the risk of the drug.

Dr. Bechtold believes the research has shed more light on the issue but warned others not to take the study in isolation.